Better handling of microbial influenced corrosion during operation

Corrosion of mild steel is a notorious problem in the oil industry, and the replacement of pipes and installations is costly. There are several types of corrosion, where pitting caused by microorganisms generate a local corrosion situation that highly reduces the quality of the steel. Although sulfate reducing bacteria (SRB) are well known contributors to microbially influenced corrosion, the mechanism behind this process as well as involvement of other bacterial groups is not well studied.

Preliminary studies showed that the Utsira aquifer water has a great corrosion potential in the systems where it is used as injection water. Furthermore, the corrosion rate increased considerable when nitrate (NO3) was added in the experiments. This is an interesting observation, as NO3 treatment has previously been used by the oil industry to limit the growth of SRB.

In this project we want to achieve a deeper understanding of the biocorrosion processes by studying the microbial community composition under heavy corrosion regimes at controlled laboratory conditions using high throughput sequencing technology in combination with electrochemical tools for corrosion rate measurements.
Furthermore, we hope to obtain new knowledge about the genes expressed by microorganisms involved in biocorrosion. So far, a non-SRB bacterial strain has been enriched at heavy corrosion conditions during to NO3 regimes, and is possibly capable of disproportionation of sulfur into H2S and SO42- which could be an important source of energy for other corrosion-associated SRB strains in the system. To resolve the metabolic and corrosive potential of the bacterial strain we intend to reveal the physiological properties through cultivation experiments and whole-genome sequencing.

Finally, we aim to study gene expression in single cells or whole communities by transcriptome and microarray analysis, where new genes involved in biocorrosion could be revealed by studying the bacterial strain during different growth conditions, and biofilms developed on corroded bioprobes. Successful identification of key genes for biocorrosion could be used to develop a lab on chip technology, a technology that can strengthen future corrosion risk monitoring, as well as better handling of microbial influenced corrosion during operation.